With the coming of spring and the rising temperatures, many people are heading outdoors to enjoy the weather and get some color back on their pale, winter skin. Why do we get tans, though?
There are two things to note about tans:
- Tanning is the result of a natural defense in our bodies, and
- The ultra violet (UV) light expelled from the sun is what gives people tans
The epidermis of our skin contains two layers, one outer and one inner. The outer layer, the one we can see, is made up of dead skins cells which constantly flake off to make room for other dead skin cells coming from the inner layer. The inner layer - called the malpighian layer - is what produces the dead skins cells that are visible to us.
There is a type of cell within this layer called a melanocyte. It produces melanin, the pigment responsible for tanning. The number of melanocytes in the body are about the same between all races. The differences in skin color between races is based on how active the melanocytes are in producing melanin. And in case you were wondering if melanoma is related to melanocytes, it is. Melanoma is caused by UV damage to the melanocytes themselves.
Tanning is actually a natural defense in our body. When the UV light from the sun hits our skin, it stimulates melanocytes to produce melanin. The melanin pigment is designed to absorb UV rays to protect other cells in the body from UV damage. It acts as a little barrier in the same way that an umbrella stops the rain from getting you wet. Melanocytes produce melanin at a slow rate after being exposed to UV light which is why it may take a few days to see a visible tan on your skin as a protective layer is built up.
While caucasians rely on UV light to produce melanin, other races have a continuous production of melanin. This means that the skin is always colored and better protected. According to Melanoma Center, race is the number one risk factor for developing melanoma.
Race is the primary risk factor for developing melanoma, with fair-skinned races at significantly greater risk than darker-skinned races. This is because darker-skinned races produce more melanin, the pigment that gives color to skin and hair, and protects the skin against damage from ultraviolet radiation. In the United States, white Americans are 20 times more likely to develop melanoma than African Americans. Worldwide, white populations have the highest risk of developing melanoma, and Asian populations the lowest risk.
Melanocytes produce melanin pigment in two varieties: red/yellow (phaeomelanin) and brown (eumelanin). Those who do not tan that well produce more phaeomelanin than eumelanin.
People who are albinos do not produce any melanin at all. This is because tyrosinase, an enzyme necessary for the production of melanin, is not present in their bodies.
A sunburn occurs when you are exposed to UV light for too long without optimal protection (i.e. a tan, sunscreen, or both). The radiation causes cell damage, and as a result blood flow is increased to the damaged area so cells can be brought in to make repairs. The high blood flow is what gives a sunburn its red appearance.
When is the best to go out and get a tan? After researching on the internet for this subject, most sources report that from 10 a.m. to 3 p.m. is when the UV light is at its strongest (others say it begins at 11 a.m., goes until 2 or 4 p.m., etc). Essentially, the higher the sun is overhead, the more UV light will be available for absorption.